The prior art method of treating metallic articles of high corrosive characteristics has been to apply some method for solely removing the mill scale, the heat treat scale, the rust, and other surface contaminates and thereafter applying a protective coating to the cleaned surfaces. The cleaning step has been done predominantly by the so-called "acid pickling" method although in some instances where there are very little surface contaminates, the surfaces have been cleaned by other methods such as by tumbling in a media which by reason of the media's tumbling over the surfaces eventually cleans the surfaces of the articles to be protected against corrosion.
In these prior methods, the sole purpose and intention of the method was to clean the surface of the scale, rust and other contaminates so that the protective coatings would adhere more readily and with greater tenacity.
These methods of treating metallic articles for corrosion protection have all left a great deal to be desired in the protective characteristics of the metallic articles after such treatment. Therefore, there has been a demand for some time for a new method for treating metallic articles to give them adequate corrosion protection.
In an entirely unrelated art to that of rust corrosion resistance there have existed for some time methods and apparatus for treating parts which required high fatigue and high stress resistant characteristics. Such articles, for example, are the vanes and other parts used in jet engines for which the United States government has set high standards for treating such components by blasting the surfaces thereof with small particles so as to peen the surfaces in order to reduce the incidences of fatigue and stress failure. An example of such procedures is found in the U.S. Government Specification entitled Military Standard Glass Bead Peening Procedures NIL-STD-852 (USAF) Sept. 21, 1965. Another example of such procedures established by private industry is the Society of Automotive Engineers Aerospace Material Specification #AMS 243 OH. Although such glass peening procedures as disclosed in the above cited documents have been in existence for a number of years as evidenced by the 1965 date of one of the documents cited above, no one to my knowledge has ever conceived, prior to the present invention, of treating articles for rust corrosive resistance by blasting the part to be treated with glass beads.